Fuel injection means



July 7, 1959 R. J. HAEFNER 2,893,365

FUEL INJECTION MEANS v Filed May 51. 1956 l 54 All,

INVENTOR Attornev .substantially atmospheric air around the nozzle.

run smoothly, particularly during idling.

United states' Faremo FUEL INJECTION lRaymond J. Haefner, Utica, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 31, 1956,'serta1N0. 588,451 3 claims. (ci. 12s-119) 'Ifhe present invention relates to internal combustion engines and more particularly to means for injecting fuel into the charge for the cylinders.

' In the operation of an internal combustion engine, the

passage it will be subject to such fluctuating pressures. Accordingly, it is desirable to isolate the fuel in the nozzles and the fuel system from the effects of these pressure changes. If this is not done the variation in the v pressures in ltheinduction air will override the metering mechanism and cause an inaccurate metering of Ithe fuel. One simple and very successful means for isolating the fuel in the nozzles from the effects of the induction pressure is to incorporate the nozzle in an injector assembly having a vent that will create an envelope of I The fuel from the nozzle and the air in the envelope flow through a small orifice and into an induction passage.

' Thus the fuel will be discharged into an envelope of air at a substantially constant pressure and thel nozzle will be isolated from the intake vacuum. Since the air in the envelope flows through the orifice and is consumed in the engine, it is desirable to limit the `amount of such air iiow to less than the amount required for idling "theengine In addition, where there are a multiplicity lof ,nou/les, it is desirable that the air supply to the envelopes produce substantially ident-ical amounts of air flow through the orifices as otherwise the engine will not i Accordingly, a vent manifold may be provided for supplying the air -tothe individual envelopes in the nozzles. Normally the air will always flow in one direction through the nozzle, i.e., the intake vacuum will cause the air in the envelope to be drawn into the intakepassage. However, under some circumstances, for example the closing of an intake valve, there may be surges of air or other conditions that will result in a transient condition in which the air y flow will reverse itself and disrupt the flow of fuel through the orifice and into the intake passages. This may cause inaccurate metering of the fuel and in the event there is a common vent manifold for supplying air to the nozzles, some of the fuel intended for one cylinder may be blown into the vent manifold and carried into another nozzle and thence into another cylinder, thereby resulting in uneven fuel distribution.

It is now proposed to provide an injector nozzle system in which a vent manifold common to all of the nozzles may supply separate quanti-ties of air to the nozzles `without in any way impairing the uniformity of the fuel distribution or the accuracy of the metering act-ion. This s to be accomplished by providing injector assemblies in which the nozzles are disposed in chambers that contain the isolating envelope of atmospheric air. An ori- `ficethrough whichthe fuelmust pass is disposed atap- ICC proximately the lowest point in the chamber. Thus the bottom of the chamber will act as a sump to collect any stray fuel which fails to immediately pass through the oritice and to retain the stray fuel immediately adjacent the orifice so that it may subsequently pass therethrough. A vent manifold supplies the air for the envelopes through inlets in the tops of the chambers. The inlets are preferably disposed adjacent the highest point in the chamber and remote from the orifice. Thus any fuel that does not pass through the orifice will collect in the sump and be prevented from entering the manifold and thereby passing from one injector assembly to another. Thus even if a surge of air in an induction passage should temporarily prevent the iiow of fuel through an orifice, the fuel will be confined to the area around the orifice and as soon as more favorable conditions are restored, the fuel will drain into its intended induction passage. It will thus be seen that each and every cylinder will receive identical quantities of correctly metered fuel.

In the one sheet of drawings:

Figure 1 is a plan view of an engine employing a fuel injection system embodying the present invention.

Figure 2 is a fragmentary view of the engine taken in the direction of arrow 2-2 in Figure l with parts broken away and in section.

Figure 3 is a cross sectional view on an enlarged scale of a fuel injector assembly.

Although the present invention may be used on any suitable engine, in the present instance it is especially adapted to be employed on a so-called V-type engine 10 having a cylinder block 12 with a pair of angularly disposed cylinder banks 14. Separate cylinder heads 16 are secured to the banks 14 so that cavities therein will register with the open ends of the cylinders. These cavities together with the upper ends of the pistons 18 reciprocably disposed in the cylinders form the combustion chambers 20. In order to charge the cylinders an induction system 22 may be provided that includes an intake manifold 23 having a throttled inlet 24 and a plurality of ram pipes 26 that interconnect the plenum chamber 28 with the intake passages 30 in the cylinder heads 16. Intake valves 32 are disposed in the intake passages 30 to time the iiow into the cylinders. It has been found advantageous to tune the ram pipes 26 in accordance with the charging of the cylinders so that they will resonate during one or more engine operating conditions and thus the surges of `air therein will tend to supercharge the cylinders.

In order to form a combustible charge of air and fuel, a fuel injection system 34 may be provided for metering and distributing the fuel to the charges for the cylinders. This fuel system 34 may include a metering unit 36 responsive to the fuel demands of the engine 10` for controlling the flow of fuel therethrough. In order to distribute this metered fuel to the various cylinders, separate injector lines 38 may be provided for each cylinder so as to radiate from the metering unit 36. Tihe outlet end of each of these injector lines 38 may be equipped with separate injector assemblies 40 that are positioned to discharge the metered fuel into the induction passages. Although the injector assemblies 40 may be mounted at any suitable location it has been found desirable to mount the assemblies 40 on the intake manifold 23 adjacent the ends of the ram pipes 26 for spraying a stream of fuel into the intake passage and toward the intake valve.

It should be noted that if the injector assemblies 40 communicate with induction passages 42, they will be subject to the effects of intake vacuum. Since the intake vacuum varies over a very wide range the head opposing the discharge of the fuel into the induction passages 42 will also vary and cause a considerable variation in the flow of metered fuel. In fact, under Asome aseaas conditions the vacuum may even become large enough to 'cause unmetered fuel Jflow from the injectionsystem 34 and/or the formation of fuel vapors in the injector lines 38.

from'the elfects'of the intake' vacuum,`thefinjectordassemblies 40 may besimilar to those disclosed and clarr'ned in copending application SeriahNorS 12,175, Fuel lnjection Nozzle iiledl May 31,1955', in the namesoMax Homfeld and Stephen Kalmar vandnow abandoned. lIn the presentinstance the injectorassernblies '4h 'are disposed in .a `passage'44 extending downwardly-`from the /face"'46 of a padf48on thesideof 4the* intake manifold 23. -`'I lhis passage 44 visoblique to the induction passage Z, so'that itopens fthereinto 'willbe aimed 'in the generalldirectionof the intake Valves `-312.

injector,assemblytlfincludes a member t) having a cylindrical'ejrterior that fits intofthe passage 42 Ysothat'lthe end thereof will rest on a shoulder SZin the passage 42'. A spring clamp 54 fastened to they 'face 46 may retain the memb'erfSt't in the passage 42. Tlhe member* 5'0 includes'a lowerV portion56 and an upper 'portion 58 that are separatedfrom eachother by a chamber 60. The lower portion "56 includes a conical depression L62 that'forrnsone end of the. charnberoii` and a small diameter passage or -orifice 64 'that extends the rest of `theway through the ,lower portion 456 to interconnect the chamber'60 with the induction passage 4Z; The

upper portion 58 of the member 50 includes' a nozzle 66- that-'p'rojects intoisaid chamber 60 concentric with the passage 42 and is aimed at the orifice 64. A passage 6 8ge`jrtends1through'the vupper portion 58 so as to be in- `:te'r'ccinnected with vtheoutlet"end of the injector line 33.

Thus the nozzle 66 may ldirect a stream fof metered fuel thro'gh said oifice'64- and into said induction passage 42 in, the directionof the intake valve 32.

side ofthe c thamber 60. By continuously supplying air to "this 'chamber 6(1)the pressureof the air in the envelope may be maintained at a substantially constant `value`which approximates atmosphericpressure irrespective of the vacuum present inside of the manifold 23. In order to maintain the pressure in the envelope yat or near atmospheric pressure it is necessary to provide a frelativelydunobstructed source of airito thechamber 60"so that the orifice 64- will be ythe primary factor limitingthe air flow into the induction passage 42. This air preferably/,enters the chamber) by an entrance 68 located at or immediately adjacent the upper end of the chamber'60. Thus the entrance 68 to the chamber 6i) will be disposed remote from and considerably above the orifice 64 and the jsump. Consequently, any fuel which fails to immediately pass throughfthe orice 64 will collect aroundthe orifice 64 andv will not 4corne near the entrance 68. This will eliminatethe,t'endencyfor any fuel that is intended to pass Vthrough the orilice 64 leaving through the entrance 68. u In order to conveniently filter anduniformly regulate the flow of air to the chambers 60, it may be desirable to provide a ventmanifold '7f3 Vsuchas disclosed vand claimed in copending `application Serial No. 512,170, Atmospheric Vent for Fuel -lnjection Nozzle -iiled May 3.l,`l955in the names of John Dolza and Raymon I.' k`Haefner now Patent No. 2,833,260, is-

sued May6, 1958.' V'.Thismanifold '70 includes a filter v inlet72 Vand, a pair oflarms 'V74 that extend along -thetwo cylinders. .Thislarrapgement will insure a Vil common supply of air to all of the envelopes. However, since the entrances 68 to the chambers v60 are arranged to prevent the escape of any fuel therethrough, there will be no maldistribution of the fuel.

During normal operation of the engine 10 there will be a small amount of air flowing through the vent manifold 70 and into the chambers 60 -to form envelopes of atmospheric zair aroundY thenozzlesti.` This air will then flow througlf'the orifices 6'4 and into vthe induction passagesAZ. Atpthesame .time the primary .supply of air will enter the y,throttle valve inlet y24 and ow through the ram pipes 26 to the cylinders. The metering'mechanisrn 34 will be eiectivel-to sense v' theffuel demands of the engine'ltl and( to meter the fuel in proportion thereto. This supplyrof meteredv fuel will-v then be forced to flow through the injector lines 3S and into injector assemblies 4t). The fuel will be discharged from Ithe nozzle v66 as a `streamairned to pass through. theoritice 64 and mix with the chrlrgein the induction:passagesv 42. Although the entire stream .of fuel -is intendedto uninterruptedly iiow through'` an korifice A64:there may be periods duringwhich this` condition does .not prevail. Eor example, ,when an intake ',valve. suddenly closes,` `it may cause a surge of `air to be reflected backupjthezin duction passageY 4t2. rl'his surgeof airrnayhaveisuflcientfpressure to' ca use a. small puff of air to be blown fromV the ,induction passage 42 through the.orii ice64 and into the chamber 60. -Since this pufI" .will bef of very short duration andthe orifice 64 is of :small s ize,

fthe puff wilhquickly dissipateitself in thevvchamber60,

Thus if thefuel stream has lvery little inertiathe pun' can cause the -fuel to be blown backintothe chamber 60( ThisV `fuel Ywill tend to collect inthe sump formed fby the bottom-of the chamber .'60 4around the orifice 64. lSubsequently, when the air ow'vfrorn ,the chamber 60 through the orifice 64 and intothe induction'passageAZ is restored, lthe fuel .will again .pass ,through theoriijice Maand be mixed with' the charge. YV'I 'hu'sfall ofthe. nietered fuelWill-be consumed inthe. cylinderfforV which it Aisintenderl.A i "Y y l Y i' Various changes and modicationsof Vthe embodiment of the invention described ,herein may be madeby those skilled in the art without departinglfroin the spirit .and principles of the invention. l

I claim: i

l. in an enginel having a cyl-inderwith an induction passagey interconnected therewith by means of a'nwint'ake valve, an injector assembly adapted to `befmounted`fin a passageextending through as'ide wall of saidinduction passage for spraying metered quantities offuel into' said induction passage in the direction'offsaid'intake valve,

ysaid injector assembly comprising an elongated fchamber having an orifice at the lower end thereof opening into Vsaid induction passage, said chamberbeing .inclined to the horizontal toforr'n asump adjacent 'said orifice positioned to collect lfuel therein, said'fsump tapering toward said orifice, Va nozzle disposedk in saidl chamber and being connected to a source ofzkmetered fuelfor discharging a stream of said metered` fuel therefrom, said nozzle being disposed in spacedrelation to s aid opening for directing saidvstreamof f uel therethrough and toward said intake valve, and a comparatively unrestricted air entrance into said chamber disposed above said sump for supplying air to said chamber.

2. In an engine haying a plurality ofcylinders ,and an induction system with induction lpassages for charging said cylinders, a plurality of injector assemblies for spraying metered quantities of fuel from a fuel metering system into said induction passages and a vent manifold, each of said assemblies. comprising an -elongated chamber having` an orifice at the lower end thereof opening into one of said induction passages, saidfchamtapered sump to drain through said orifice into the induction passage, a nozzle disposed in said chamber and being connected to said fuel system for discharging a stream of fuel therefrom, said nozzle being positioned in spaced relation to said opening for directing said stream of fuel therethrough and into said induction passage Vand an air entrance into said chamber disposed remote from said opening and above said sump, said vent manifold being interconnected With said entrances for supplying air at substantially atmospheric pressure tc said chambers.

3. In a V-type engine having a pair of angularly disposed banks of cylinders, an induction system having induction passages for charging said cylinders, fuel nozzles disposed in separate chambers for directing streams of metered vfuel from a fuel system through restricted orifices in the bottoms of said chambers and into said induction passages, each of said chambers having sub stantially unobstructed inlets opening into the tops thereof, a vent manifold connected to said inlets for supplying atmospheric air to the tops of said chambers that may pass through said oriiices and into said induction passages, said chambers being arranged to`form conical sumps having their apices terminating in the restricting orifices of said chambers so that any residual fuel in said chambers will collect in said sumps and drain through said orices with said air.

References Cited n the le of this patent UNITED STATES PATENTS 2,157,034 Tice May 2, 1939 2,511,213 Leslie June 13, 1950 FOREIGN PATENTS 520,965 France Feb. 24, 1921 710,213 Great Britain June 9, 1954 

